<!DOCTYPE html>
<html>
  <head>
    <style>
      #t { background: green; position: absolute; width: 100%; left: 0;
           height: 10px; top: 0; }
    </style>
  </head>
  <body>
    <div style="position: relative; display: inline; color: white; background: white;">ABCDEF<div id="t"></div></div>
  <body>
</html>
